Steam generator



Nov. 29, 1932.

H. J. KERR STEAM GENERATOR Filed July 6, 1929 INVENTOR J/f/a/ ATTORNE 5 Patented Nov. 219A, 1932 vIren STATES insana PATENT oFFlcE HOWARD J. KEER, F WESTFIELD, NEW' JERSEY, ASSIGNOR TO THE BABCOCK & WILCOX COMPANY, OF BAYONNE, NEVI JERSEY, A CORPORATION 0F NEW JERSEY STEAM GENERATOR Application filed July e, 1929. Serial No. 376,297.

This invention relates to a steam generator comprising two boilers, one of which is heated largely by radiant heat and the other is heated by convection gases. The boilers have different water levels with their steam spaces connected during normal operation. Provision is also made to cause circulation vof water to talre place from the convection heated` boiler through the tubes of the other boiler during the starting up period to avoid the occurrence of Water hammer troubles in the steam and water drum of the convection heated boiler.

The invention will be understood from the description in connection with the accompanying drawing in which Fig. 1 is a vertical section through an illustrative embodiment of the invention; and Fig. 2 is a section taken along the line 2-2 of F ig. 1.

In the drawing reference character 1 indcates a furnace above which a boiler of the Babcock & VVilcoX type is located, having a steam and water drum 2, downtake headers 3 and uptake headers 4 connected by a bank of inclined tubes 5. A. mud drum 6 is nippled to the lower ends of the headers 3 and a valved drain pipe 7 is connected to the mud drum 6.` A steam pipe 8 extends from the steam space of the steam and water drum 2 to the superheater 8 from which steam passes to a steam main. An economizer 9 is located in a flue for the outlet gases after they have passed over the boiler heating surfaces of the boiler just described.

A downtalre pipe 10 provided with a valve 10 extends downwardly lfrom each end of the water space of the steam and water drum 2. Valved branches 11 extend from the pipes 10 to horizontally disposed headers 12 located along the lower edges of theside walls of the furnace 1. Valved branched pipes 13 also extendv from the pipes 10 to horizontally disposed headers 14 located on opposite sides of the lower end of the ash hopper 15. Rows of tubes 16 along the sloping walls of the ash hopper connect the headers 14 to the headers 17 and 18, respectively, located along the lower edges of the front and rear ywalls of the furnace 1. A row of furnace wall tubes 19 extendsalong the rear wallfof the. furnace from the header 17 to the header 2O.l A'row of furnace wall tubes 21 extends along the front wall of the furnace from the header 18 lto the steam and water drum 22. One or more fuel burners 23 are'located along the front 55 wall of the furnace 1. A row of tubes 24 eX- tends across the upper end of the furnace 1 from the header into the steam and water drum 22.

A drum 25 is located near the upper edge 60 of the rear wall of the furnace and is connected to the drum22 by-means of a banlr of inclined tubes 25. A feed water inlet 26 from a feed water pump (not shown) is connected to the drum 25. Rows of tubes 27 65 located outside of the furnace, connect the drums 22 and 25 near the ends of these drums. Bows of side wal-l furnace tubes 28 connect the lower headers 12 to upper headers 29 and tubes 30 connect the headers 29 to the drum 22. 70

One or more pipes 31 each provided with valves 32 and 33 near the ends thereof connect the steamspaces of the drums 2 and 22. One or more .pipes 34 each with curves or bends therein to provide for expansion and con- 75 traction are provided with valves 35 and 36 near opposite ends thereof and connect the upper portion of the drum 22 .to the lower portion of the drum 2. A valved drain pipe 37 is provided foreach pipe 34'above the 80 lower valve 35. A safety valve`38 is provided for the drum 2 and a safety valve 39 for the drum 22.

Pipes provided with valves 41 lead from the waterv space of the drum 22 to the pipes 85 y The operation is as follows: Y

Vhen the steam vgenerator is being started up, the valves 41, 32 and 33 areclosed, while the valves 10,'35, 36 and the valves in the 90 branches 11 and 13 are opened. The radiant .heat boiler comprising the furnacew'al-l tubes is entirely filled with water, including the pipes 10 and 34, and the other boiler is filled until the drum 2 is'about half full of water. 95

downwardly through the pipes 10 into the 100 lower headers and then upwardly through the furnace wall tubes to the drum 22 and then through the pipe 34 into the drum 2. Circulation is also permitted to take place between drums 22 and 25 through the bank of tubes 25 and tubes 27. If the expansion of the water during this period increases the water level too much in the drum 2, the valve 7 is opened to drain out a portion of the water. y

When the steam pressure in the main boiler approaches the working pressure, the valves l0', 35 and 36 are closed and the valves 32, 33 and il are opened. The convection heat boiler then operates in the usual way, the water level being maintained in the drum 2 at the proper point. The radiant heat boiler is fed with water through the pipe 26 to keep the drum 22 approximately half full of water. The circulation of the water 'through the radiant heat boiler or furnace wall tubes is maintained during normal operation by water passing downwardly through the pipes 40 into the pipes l0 and thence through the branches ll and 13 to the lower headers. Also, water passes upwardly from the drum 25 through the banlr of tubes 25 into the drum 22, a portion of this water passing back to the drum 25 through the outside or colder pipes 27. rlhe steam generated in the lower boiler passes from the drum 22 through the pipe 3l into the steam space of the drum 2 and thence to the superheater 8 I claim:

l. In a steam generator, ay furnace, a boiler having furnace wall tubes and having tubes extending across the upper portion of said furnace, a boiler above said furnace, and means to establish communication between said first named boiler and the water space only of said last named boiler during the starting up period and to establish communication between the steam spaces only of said boilers during normal operation.

2. In a steam generator, a furnace, a boiler having furnace wall tubes and having tubes extending across the upper portion of said furnace, a boiler above said furnace, and means to establish communication between said first named boiler and the water space only of said last named boiler during the starting up period and to establish communication between the steam spaces only of said boilers during normal operation, said means comprising pipes with valves in them.

3. In a steam generator, a furnace, a boiler having furnace wall tubes and having a bank of inclined tubes extending across the upper end of said furnace and connected to drums along opposite sides of said furnace, a boiler above said furnace, and means to establish communication y between said first named boiler and the water space only of said last named boiler during the starting up period and to establish communication between the steam spaces only of said boilers during normal operation.

4. Steam generating apparatus comprising a furnace, a water tube boiler including steam generating surface arranged to be mainly heated by the absorption of radiant heat from said furnace and a steam and water drum connected to said radiant heat absor ing steam generating surface, asecond water tube boiler including steam generating surface arranged to be mainly heated by contact with the heating gases leaving said furnace and a steam and water drum connected to said convection heat absorbing steam generating surface and at a level substantially above the level of the steam and water drum of said first boiler, means for separately supplying feed water to said boilers, a conduit connecting the upper part of the steam and water drum of said first boiler to the steam space of the steam and water drum of said second boiler for conducting substantially all of the steam generated in said rst boiler to said second boiler during normal operation, a steam outlet connection from the steam and water drum of said second boiler', and a valved conduit system connecting the water space of the steam and water drum of said second boiler to said first boiler and operable to establish independentV water levels in said boilers during normal operation and to flood said first boiler during startingup periods.

5. Steam generating apparatus comprising a furnace, a water tube boiler including steam generating surface arranged to be mainly heated by the absorption of radiant heat from said furnace and a steam and water drum connected to said radiant heat absorbing steam generating surface, a second water tube boiler including steam generating surface arranged to be mainly heated by contact with the heating gases leaving said furnace and a steam and water drum connected to said convection heat absorbing steam generating surface and at a level substantially above the level of the steam and water drum of said first boiler, a valved conduit connecting the upper part of the steam and wat-er drum of said first boiler to the steam space of the steam and water drum of said second boiler for conducting substantially all of the steam generated in said first boiler to said second boiler during normal operation, a steam outlet connection from the steam and water drum of said second boiler, meansfor separately supplying feed` water to said boilers, and a valved conduit system connecting the water space of the steam and water drum of said second boiler to said first boiler and operable to establish independent water circulation paths in said boilers during normal operation and connected water circulation paths during starting-up periods.

6. Steam generating apparatus comprising walls defining a furnace chamber, a heat-ing gas pass in communication with said furnace chamber, a steam generating section including a bank of convection heated Water tubes in said gas pass, and a steam and Water drum connected to said tube bank and having a steam outlet connection therefrom, a second steam generating section including a plurality of water tubes arranged to absorb radiantheat from said furnace chamber and a steam and Water drum connected to the discharge ends of said radiant heat absorbing Water tubes and below the level of the steam and Water drum of said first steam generating section, a con duit connecting the steam spaces of said steam and Water drums, a valved conduit connecting the steam and Water drum of said second steam generating section to the water space of said first steam generating section, a valved connection between the water space of said first steam generating section and the inlet ends of said radiant heat absorbing water tubes, and separate water supply connections to said steam generating sections, whereby the water iow circuit through said radiant heat absorbing Water tubes may be varied to include or exclude a. portion of the water space of said first steam generating section as operating conditions require.

7. Steam generating apparatus comprising walls defining a furnace chamber, a heating gas pass in communication with said furnace chamber, a steam generating section including a bank of convection heated water tubes in said gas pass, and a steam and water drum connected to said tube bank and having a steam outlet connection therefrom, a second steam generating section including a plurality of water tubes arranged to absorb radiant heat from said furnace chamber, a steam and water drum connected to the discharge ends of said radiant heat absorbing water tubes and below the level of the steam and water drum of said first steam generating section, and a conduit connecting said last mentioned steam and water drum to the inl-et ends of said radiant heat absorbing water tubes, a conduit connecting the steam spaces of said steam and Water drums, a

valved conduit connecting the steam and water drum of said second steam generating section to the Water space of said iirst steam generating section, a valved connection between the water space of said first steam generating section and the inlet ends of said radiant heat absorbing Water tubes, and separate water supply connections to said steam generating sections, whereby the Water flow circuit through said radiant heat absorbing water tubes may be varied to include or exclude portion of the water space of said first steam generating section as operating conditions require.

HOWARD J. KERR. 

